Computerized transaxial x-ray reconstruction has recently become comercially available for studies of brain lesions, and it is believed that there may be institutions or companies that are developing this technique further and are building equipment that is capable of performing the same function for the torso and parts thereof. The government is seeking offerers who have the capability and interest to develop analog, digital, or hybrid algorithms for computerized transaxial x-ray reconstruction, with the objectives of enhancing the detection and/or localization of lesions, particularly early or small leasions, and developing criteria for evaluating the efficiency of such algorithms. These research efforts should include three dimensional reconstruction of absorption densities in any direction, minimize the deleterious effects of distortion and artifacts in regions of medical interest, and tend to disease scan time and radiation risk to the patient.